CN1246713C - Optical-fiber array - Google Patents

Abstract

In an optical fiber array, an optical fiber, a bundle of optical fibers or an optical fiber ribbon is mounted on an array substrate with a V-groove or V-grooves. A bare fiber portion in which a fiber coating is removed is placed in the V-groove, pressed by a presser member 6 and bonded by adhesives. At the front end, the fiber(s) is/are accurately positioned to connect to optical components or PLCs. The bare fiber portion contains a spliced portion of the dissimilar optical fibers having different mode field diameters and a mode field converting portion. The spliced portion of the dissimilar optical fibers is mounted on the array substrate. A flexible protection member is provided in the fiber coating portion extending over a rear edge of the array substrate. The optical fiber is bonded onto the array substrate, employing three kinds of adhesives that are different in the Young's modulus after hardening and the viscosity before hardening.

Description

Fiber Array

technical field

The present invention relates to an optical fiber array, wherein an optical fiber, a bundle of optical fibers or an optical fiber ribbon is attached and fixed to an array substrate, and the array substrate is used to connect an optical fiber or an optical fiber ribbon to an optical element or a planar light wave Circuit (planar light wave circuit) (PLC).

Background technique

In an optical fiber communication system, an array of optical fibers is used to connect an optical fiber to an optical component or PLC. The optical fiber array generally includes an array substrate having V-shaped grooves, each V-shaped groove for receiving an end of an optical fiber, and a cap for pressing the end of the optical fiber into the V-shaped groove. The optical fiber includes an optical fiber and an optical fiber ribbon, wherein a plurality of optical fibers are integrally fixed together with a ribbon or resin. The optical fiber array is made by placing the end of the optical fiber in the V-shaped groove, pressing the end of the optical fiber into the V-shaped groove with a cover, using an adhesive to fix the optical fiber on the array substrate, and then polishing to expose the optical fiber. made of the front end of the array substrate.

In recent years, an optical fiber needs to be connected to a PLC having a different mode field diameter (mode field diameter smaller than the ITU-T standard size) from a standard single-mode optical fiber. In this case, an optical fiber with a smaller mode field diameter is used to connect to the PLC, and an optical fiber with a standard mode field diameter is used to connect to the cable side. In an optical fiber array for connection with a PLC, an optical fiber with a small mode field diameter is fusion-spliced at the tip of an optical fiber with a standard mode field diameter, which causes a large splice loss.

When splicing a number of non-standard fibers with different mode field diameters and standard single-mode fibers, it is difficult to obtain practical splice loss only by the usual fusion splicing technique. Generally, an existing method is to melt and splice the optical fiber and additionally heat the spliced portion of the optical fiber (thermal expansion core, hereinafter referred to as TEC or TEC treatment) to reduce the splicing loss (for example, see JP2618500 and JP- A-2000-275470). By this additional heating, the dopant added to the core of the fiber is thermally diffused into the cladding of the fiber, so that the mode field diameter is locally enlarged. Therefore, the mode field diameters of the optical fibers coincide with each other at the junction.

Contents of the invention

An object of the present invention is to provide an optical fiber array that can be reduced in size, can prevent breakage when the optical fiber is bent or is applied with tension, and can prevent an increase in transmission loss due to temperature change.

According to the present invention, there is provided an optical fiber array comprising: forming an optical fiber by splicing different optical fibers having different mode field diameters, the optical fiber having a fiber coating portion to which a fiber coating is applied and a bare fiber portion from which the fiber coating is removed, The center of the bare fiber portion has a splicing portion of different fibers; an array substrate for mounting fibers thereon, the array substrate has a fiber alignment portion and a base portion, the fiber alignment portion has a bare fiber for placing the fiber The V-shaped groove of part; Presser part, is used for this bare optical fiber part is pressed on the V-shaped groove of array substrate; And first adhesive, is used for this bare optical fiber part is fixed to the V-shaped groove of array substrate. On the shape groove, it is characterized in that the bonding part of different optical fibers is placed on the array substrate; wherein the optical fiber array further includes: a second adhesive, used to fix the optical fiber coating part of the optical fiber on the base of the array substrate and a third adhesive for covering and fixing the bare optical fiber portion not placed in the V-groove, wherein the first adhesive has a Young's modulus of 500Mpa or more after hardening and before hardening Having a viscosity of 10 Pa.s or less, the second adhesive has a viscosity greater than that of the first adhesive before hardening, and the third adhesive has a higher viscosity than the first adhesive after hardening The Young's modulus of an adhesive is smaller than the Young's modulus. Preferably, a flexible protective member is provided on the optical fiber coating portion extending over the rear edge of the array substrate. In addition, the optical fiber can be bonded to the array substrate with three types of adhesives that differ from each other in Young's modulus after hardening and viscosity before hardening.

The present invention also provides an optical fiber array, comprising: forming an optical fiber by splicing different optical fibers having different mode field diameters, the optical fiber has an optical fiber coating portion to which the optical fiber coating is applied and a bare optical fiber portion from which the optical fiber coating is removed, the bare optical fiber The center of the part has a splicing portion of different optical fibers; an array substrate for mounting optical fibers thereon, the array substrate has a fiber alignment portion and a base portion, the fiber alignment portion has a V for placing the bare fiber portion of the optical fiber Shaped groove; Presser part, is used for this bare optical fiber part is pressed on the V-shaped groove of array substrate; And first adhesive, is used for this bare optical fiber part is fixed on the V-shaped groove of array substrate , which is characterized in that splicing portions of different optical fibers are placed on the array substrate; wherein the array substrate has a tapered or arc-shaped rear end portion.

The present invention also provides an optical fiber array, comprising: forming an optical fiber by splicing different optical fibers having different mode field diameters, the optical fiber has an optical fiber coating portion to which the optical fiber coating is applied and a bare optical fiber portion from which the optical fiber coating is removed, the bare optical fiber The center of the part has a splicing portion of different optical fibers; an array substrate for mounting optical fibers thereon, the array substrate has a fiber alignment portion and a base portion, the fiber alignment portion has a V for placing the bare fiber portion of the optical fiber Shaped groove; Presser part, is used for this bare optical fiber part is pressed on the V-shaped groove of array substrate; And first adhesive, is used for this bare optical fiber part is fixed on the V-shaped groove of array substrate , characterized in that splicing parts of different optical fibers are placed on the array substrate; wherein the optical fiber array further includes: a protective component for protecting the optical fibers extending at the rear edge of the array substrate.

6 is a schematic diagram showing an example for splicing PLC and standard single-mode fibers with different mode field diameters using a fiber array combining TEC fiber technology and fiber array technology. In Fig. 6, reference numerals 1, 1a, and 1b denote optical fibers, 2 denotes a fiber coating portion, 3 denotes a bare fiber portion, 4 denotes an optical fiber array, 5 denotes an array substrate, 6 denotes a presser part, and 7 denotes a V-shaped Grooves, 8 and 9 represent adhesives, 10 represents a joint portion, and 16 represents a reinforcing member.

The optical fiber 1 has an optical fiber 1b with a smaller mode field diameter and an optical fiber 1a with a larger mode field diameter (standard single-mode fiber). The optical fiber 1b is fusion spliced to the tip of the optical fiber 1a. The joint portion 10 of the optical fibers 1a, 1b is protected by a reinforcing member 16 . In order to reduce bonding loss, the bonded portion 10 is subjected to a TEC treatment, which involves additional heating after melting the bond. The optical fiber 1b is bonded to the array substrate 5 using an adhesive. The splicing portion 10 is protected by a reinforcing portion 16 and placed outside the optical fiber array 4 .

The reinforcing member 16 of the splice portion 10 to be fusion spliced needs to have the same size as the outer shape of the optical element, and have a relatively large space for guiding the optical fiber. Therefore, there is a problem that it is difficult to miniaturize the optical fiber communication unit due to the presence of the reinforcing member 16, and it is not easy to attach and detach.

The optical fiber array 4 includes an array substrate 5 and a presser part 6 . The array substrate 5 includes an optical fiber alignment portion 5a having a V-groove 7 at the front and a base portion 5b at the rear thereof. After the adhesive 8 is applied to the V-groove 7 of the fiber alignment portion 5a, the optical fiber 1b is inserted into the V-groove 7 at the front end of the bare fiber portion 3 where the fiber coating has been removed, passed through the presser member 6 Press into place and bond via adhesive 8.

A portion of the adhesive 8 in the V-groove flows out to the base portion 5b, and covers the rear end portion of the bare optical fiber portion 3 protruding from the rear end of the V-groove. In addition, a portion of adhesive 8 flows between the fiber covering portion 2 and the base portion 5b to join the rear end portion of the bare fiber portion 3 and the front end portion of the fiber coating portion 2 on the base portion 5b. In addition, in order to restrict the free movement of the optical fiber 1b at the rear end of the optical fiber array, an adhesive softer than the adhesive 8 is used to bond the optical fiber covering portion 2 to the rear end portion of the base portion 5b.

With the structure of the optical fiber array described above, the optical fiber 1 is in contact with the rear edge 5c of the array substrate 5 . Therefore, the optical fiber 1 may be disconnected by being bent at the rear edge 5c of the array substrate 5, or the splice loss may increase due to a temperature change.

However, since the array substrate 5 is made of various wafers such as silicon, borosilicate glass, zirconia or ceramics, the tapered surface is formed by precisely grinding such as cutting. In this grinding, special precision blades are used and high working precision is required. A method is currently known for forming a conical surface by grinding, but this requires considerable work time and manpower. In addition, a method of forming the tapered surface by injection molding can be considered, but there is a problem in that injection molding is difficult due to the material of the array substrate.

And it is also known that if a hard adhesive resin having a relatively large Young's modulus is used as the adhesive 8 coated on the entire bare optical fiber portion 3 when splicing the optical fiber 1, this increases the transmission loss of the optical fiber at low temperature . Therefore, it is considered that the adhesive resin shrinks at a low temperature, so that the optical fiber is pulled onto the upper surface of the array substrate by the thermal contraction of the adhesive resin. In addition, the adhesive 9 applied to the optical fiber covering portion 2 is an adhesive resin which is softer than the adhesive 8 . Since the adhesive 8 is rarely applied to the portion of the fiber covering portion 2, a pulling force is applied to the bare fiber portion 3 from which the fiber coating is removed which is weaker against the pulling force. Therefore, when a pulling force is applied to the optical fiber 1 in the longitudinal direction or the optical fiber is bent at the rear end, the optical fiber 1 is easily broken at the bare fiber portion 3 .

And, if a soft adhesive resin having a relatively small Young's modulus is adopted as the adhesive 8 coated on the bare optical fiber portion 3, even if the adhesive 9 is applied to the optical fiber coating portion, the optical fiber The overall resistance to pulling force is weak. That is, in a structure in which the optical fiber 1 is bonded to the optical fiber array 4 by one or two kinds of bonding resins, it is difficult to avoid an increase in transmission loss due to temperature change as shown in FIG. requirements under tension.

Description of drawings

FIG. 1 is a schematic diagram illustrating an optical fiber array according to an embodiment of the present invention;

2A-2C are schematic diagrams illustrating forms of splicing optical fibers with different mode field diameters used in the present invention;

3A-3C are schematic diagrams showing an example in which an optical fiber splice formed by melting has an expanded portion;

FIG. 4 is a schematic view showing an example of a tubular protective member used in the present invention;

5A and 5B are schematic diagrams showing an example of a molded protection member used in the present invention; and

FIG. 6 is a schematic diagram for explaining the structure of a conventional optical fiber array.

Detailed ways

A preferred embodiment of the present invention will now be described with reference to Figures 1 and 2A-2C. Figure 1 shows a basic embodiment of an optical fiber array of the present invention. 2A-2C illustrate various forms for splicing optical fibers having different mode field diameters. In these figures, reference numeral 1 denotes an optical fiber, 2 denotes an optical fiber coating portion, 3 denotes a bare fiber portion, 3a and 3b denote bare optical fibers, 4 denotes an optical fiber array, 5 denotes an array substrate, 5a denotes a fiber alignment portion, 5b denotes Base part, 6 denotes the presser part, 7 denotes the V-shaped groove, 10 denotes the engaging part, 10a denotes the expansion part, 11 denotes the first adhesive, 12 denotes the second adhesive, 13 denotes the third adhesive , 20a and 20b represent the cladding portion, 21a and 21b represent the core wire portion, and 22a and 22b represent the mode field conversion portion.

The shape of the optical fiber array 4 shown in FIG. 1 is similar to that shown in FIG. 6 . However, the optical fiber array 4 includes an array substrate 5 and a presser member 6 . The array substrate 5 includes an optical fiber alignment portion 5a at its front and a base portion 5b having a flat upward surface at its rear. The fiber alignment portion 5a has a V-groove 7 for placing the bare fiber portion 3 from which the fiber coating has been removed.

The bare fiber portion 3 on the array substrate 5 has a bare fiber from which the coating of the fiber has been removed, and a bare fiber 3b of a different kind from the bare fiber 3a, as shown in FIGS. 2A-2C. A bare optical fiber 3b is spliced to the tip end portion of the bare optical fiber 3a. The bare optical fiber 3a is, for example, a standard single-mode optical fiber, and has a cladding portion 20a and a core portion 21a. The mode field diameter of the core wire portion 21a is about 10 micrometers. The bare optical fiber 3b is, for example, a non-standard optical fiber having a dopant added at a high density in the core portion 21b, and has a cladding portion 20b surrounding the core portion 21b. The mode field diameter of the core wire portion 21b is about 5 micrometers.

The junction 10 between the bare optical fiber 3a and the bare optical fiber 3b is formed by actually joining the bare optical fiber 3a to the bare optical fiber 3b, or by melting the bare optical fibers 3a and 3b. In order to prevent joint loss due to the difference in mode field diameter at the joint, the joint 10 is subjected to TEC treatment by additional heating. Through TEC treatment, the dopant in the core part 21a, 21b of the bare optical fiber 3a, 3b is thermally diffused into the cladding part 20a, 20b to form the mode field conversion part 22a, 22b, so that the two mode fields The diameters are the same or nearly equal.

Fig. 2A shows a situation where bare optical fibers 3a and 3b are adjacent and spliced. In this case, the middle portion of the bare fiber 3b is previously subjected to TEC treatment, and then the middle portion of the TEC portion is cleaned and/or polished so that the spliced end of the bare fiber 3b matches the mode field diameter of the bare fiber 3a. 2B and 2C show the case where the bare optical fiber 3a and the bare optical fiber 3b are fusion spliced, and the splice portion 10 is subjected to TEC treatment by additional heating after the fusion splicing. TEC treatment is disclosed in Japanese Patent No. 2618500. In fusion splicing, there is a case where the outer diameter of the splicing portion 10 does not have a swollen portion like the outer diameter of the bare optical fiber, as shown in FIG. 2B . There is also a case in which the outer diameter of the splice 10 has an expanded portion 10a of the outer diameter of the bare optical fiber, as shown in FIG. 2C.

Referring back to Fig. 1, the structure for splicing the optical fiber 1 to the array substrate 5 will be described below. In FIG. 1, the bare fiber portion 3 of the optical fiber 1 has a bare fiber 3a and a bare fiber 3b in which the splicing portion has no expanded portion, as shown in FIG. 2A or 2B. In this example, the bare fiber portion 3 is mounted on the fiber alignment portion 5 a so that the joint 10 is placed in the V-shaped groove 7 of the array substrate 5 and pressed and positioned by the presser member 6 . The engagement portion 10 is engaged in the V-groove 7, reinforced and protected by an adhesive. The top end portion of the fiber covering portion 2 is mounted on the base portion 5B of the array substrate 5 , and the bare fiber portion between the V-groove 7 and the rear end of the fiber covering portion 2 is suspended on the array substrate 5 . The engagement portion 10 is not pressed into the V-shaped groove by the presser member 6 .

The bare fiber portion 3 positioned by the V-groove 7 and the presser member 6 is bonded by the first adhesive 11 . The top end portion of the optical fiber covering portion 2 is bonded to the base portion 5b by the second adhesive 12 . The bare fiber portion 3 between the first and second adhesive is bonded by the third adhesive 13 . The first adhesive 11 is a relatively hard adhesive having a Young's modulus of 500 MPa (megapascal) or more after hardening and a viscosity of 10 Pa.s (Pa. seconds) or less before hardening. mixture. The second adhesive 12 is similar to the first adhesive 11 and is a relatively hard bond having a Young's modulus of 500 Mpa or more after hardening and a viscosity greater than 10 Pa.s before hardening agent. And, the third adhesive 13 is a relatively soft adhesive resin softer than the first adhesive 11 having a Young's modulus of less than 500 MPa after hardening.

The first adhesive 11 has a relatively low viscosity so that the bare fiber portion 3 is easily aligned in the V-groove and can be correctly positioned by the presser part 6, which will be connected to the PLC. Since its Young's modulus after being hardened is large, the bare optical fiber portion 3 can be firmly bonded by the adhesive. If the second adhesive 12 has too little viscosity, it will flow away when it is applied to the upper end of the optical fiber covering part 2, so it has a higher viscosity than the first adhesive that will be firmly applied on the optical fiber covering part 2. Mixture 11 has a greater viscosity. Since its Young's modulus after hardening is larger than that of the first adhesive 11, the top end portion of the optical fiber covering portion 2 can be firmly bonded to the rear end portion of the array substrate 5.

Accordingly, during the bonding of the bare fiber portion 3 by the first adhesive 11, stress concentration on the bonded portion of the fiber covering portion 2 against the pulling force in the longitudinal direction of the fiber 1 can be avoided. Also, during bonding of the optical fiber covering portion 2 by the second adhesive 12, the movement of the optical fiber 1 is restricted, and no stress is concentrated on the bonded portion of the bare optical fiber portion 3. Therefore, the first adhesive 11 and the second adhesive 12 can provide sufficient bearing force, enough to resist the pulling force in the longitudinal direction of the optical fiber 1 .

A third adhesive 13 is applied on the bare fiber portion 3 between the first adhesive and the second adhesive to protect and bond the bare fiber portion, but it has a higher smaller Young's modulus. Accordingly, at lower temperatures, thermal shrinkage of the third adhesive 13 is reduced, causing less deformation in the bare fiber portion 3, and preventing an increase in transmission loss.

3A to 3C are schematic diagrams showing that the swollen portion 10a shown in FIG. 2C appears on the joint portion of the bare optical fiber 3a and the bare optical fiber 3b. In FIGS. 3A to 3B , the same or similar components as those in FIG. 1 are denoted by the same reference numerals and will not be described.

In the example of FIG. 3A , the engaging portion 10 is suspended on the base 5 b outside the V-shaped groove 7 , is applied with a third adhesive 13 , and engages on the base portion 5 b. The bare optical fiber 3b is only installed in the V-groove 7 to be positioned and bonded by the first adhesive 11 . The joining portion 10 is protected and reinforced by a third, softer adhesive 13 .

In the example of FIG. 3B, the array substrate 5 has a concave portion 7a formed in the middle of the V-shaped groove 7. As shown in FIG. The engaging portion 10 is placed in the recessed portion 7a. The upper portion of the recessed portion 7a is not pressed by the presser member 6. As shown in FIG. Both sides of the engagement portion 10 are supported in the V-shaped grooves. The joining portion 10 is protected and reinforced by a third adhesive 13 . Contrary to the example of FIG. 3A , in this example the engaging portion 10 is kept straighter in the V-groove and is more firmly bonded by the adhesive.

In the example of FIG. 3C, the array substrate 5 has a concave portion 7a formed in the middle of the V-shaped groove 7. As shown in FIG. The presser member 6 has a recessed portion 6a formed on the presser member 6 at a position opposite to the recessed portion 7a. Therefore, the engagement portion 10 is placed in the gap between the recessed portions 6a and 7a. The joint portion 10 is supported in this gap by the recessed portions 6 a and 7 a , protected and reinforced by the first adhesive 11 applied in the V-groove 7 . Contrary to the example of FIGS. 3A and 3B , in this example the joining portion 10 is positioned on both sides by the V-groove 7 and the presser part 6 and is joined by the first adhesive 11 with greater resistance. The strength of the pull.

3A to 3C example shown, the rear edge portion of the array substrate 5 can be formed as a tapered or arc-shaped smooth surface 5e (represented by dashed lines), to improve the distance between the optical fiber 1 and the rear edge of the array substrate 5. contact status. Therefore, the optical fiber 1 is not easily damaged by the rear edge of the array substrate 5, or is not easily bent excessively under the optical fiber array 4, reducing breakage or preventing increased transmission loss. Regardless of whether it is suspended from the base 5a and/or reinforced by adhesive, it is preferable not to contact the joint with the base part, since the joint is generally weak in tensile strength.

4 and 5A-5B are diagrams showing examples of enhancing the contact of optical fibers with the rear edge of the array substrate by using a protective member. Fig. 4 shows an example of using a pipe as a protective member. FIG. 5A shows an example of forming a protective member by injection molding a coated portion of an optical fiber and a portion of a bare optical fiber. FIG. 5B shows an example of forming a protective member by injection molding a coating portion of an optical fiber. In these figures, reference numerals 14 and 15 denote protective members. Other components are denoted by the same reference numerals as used in FIG. 1 and will not be described.

Same as shown in FIG. 3A, in FIGS. 4 and 5A-5B, the joint portion 10 between the bare optical fiber 3a and the bare optical fiber 3b is suspended on the base portion 5b behind the V-groove 7, and is glued by a third adhesive. The compound 13 is covered and fixed on the base portion 5b by the adhesive 13. However, the structures or forms shown in FIGS. 1, 3B and 3C can also be applied to this embodiment.

In FIG. 4 , a tubular protective member 14 is provided on the fiber coating portion extending on the rear edge 5 c of the array substrate 5 , thereby preventing the optical fiber 1 from directly contacting the rear edge 5 c of the array substrate 5 . The tubular protective portion 14 is formed, then the optical fiber 1 is inserted, fixed to the optical fiber covering portion 2 by an adhesive, and mounted on the array substrate 5 . However, the process can be reversed: after the tubular protective member 14 is fixed to the rear end portion of the array substrate 5 by adhesive, the optical fiber can then be inserted through the tube of the protective member 14 .

The tubular protective member 14 is formed of a soft, bendable material such as a polymer such as rubber, silicone or nylon. The protective member 14 is spaced a slight distance (for example, about 0.5 mm to 2.0 mm) from the top of the fiber covering portion 2 so that the fiber covering portion 2 not covered by the protecting member 14 can be attached to the array substrate 5 . The protective portion 14 has a certain length (for example, preferably 3 mm to 5 mm) extending from the rear end of the array substrate 5 . The protective member 14 is placed for fixation by placing its top end adjacent to the shoulder of the stepped portion 5d on the base portion 5b of the array substrate 5 .

The protective member 14 is integrally bonded to the optical fiber 1 by applying an adhesive to fill a part or the entire gap portion between the protective member 14 and the optical fiber covering part 2 . The binder can be the same as or different from the second binder. The protective member 14 may be attached to each optical fiber individually or collectively to all optical fibers, or to a fiber optic ribbon.

In the structure of FIG. 4 , the bare optical fiber portion 3 positioned by the V-groove 7 is fixed by the first adhesive 11 similarly to the case of FIG. 1 . The upper end portion of the optical fiber covering portion 2 is fixed to the base portion 5b by the second adhesive 12 . The bare fiber portion 3 between the first and second adhesive is fixed by the third adhesive 13 . The first adhesive 11 is a relatively hard adhesive having a Young's modulus greater than 500 MPa after hardening and a viscosity of 10 Pa.s or less before hardening. The second adhesive 12 is similar to the first adhesive 11, and has a Young's modulus greater than 500 Mpa after hardening and has a viscosity of 10 Pa.s or greater than the first adhesive 11 before hardening. Relatively hard adhesive with high viscosity. And, the third adhesive 13 is a relatively soft adhesive resin softer than the first adhesive 11 having a Young's modulus of less than 500 MPa.

The second adhesive 12 for bonding the optical fiber covering portion 2 on the array substrate 5 is applied to cover a part of the optical fiber covering portion 2 protruding from the top end portion of the protective member 14 and mounted on the array substrate 5 On a part of the protection part 14. Therefore, a pulling force in the longitudinal direction of the optical fiber 1 is prevented from being directly applied to the bare optical fiber portion 3 engaged in the V-shaped groove 7, as shown in the case of FIG. 1 .

The protective member 14 is provided to extend on the rear edge 5 c of the array substrate 5 and serves as a spacer that prevents the optical fiber 1 from coming into direct contact with the array substrate 5 . Moreover, the optical fiber 1 is not easily damaged by the rear edge of the array substrate 5, or is not easy to be excessively bent under the optical fiber array 4, so as to reduce breakage or reduce transmission loss, without making the rear edge of the array substrate 5 as A smooth surface, as shown in Figures 3A-3C.

In an example of FIG. 5A , a mold is used to form the protective member 15 to cover the end of the fiber covering portion 2 of the optical fiber 1 and a part of the bare fiber portion 3 . The protection member 15 is provided to extend over the rear edge 5c of the array substrate 5, preventing the optical fiber 1 from coming into direct contact with the rear edge 5c of the array substrate 5.

In an example of FIG. 5B, a mold is used to form the protective member 15 to cover the periphery of the end of the fiber covering portion 2 for the optical fiber 1, so that the top end of the fiber coating portion protrudes slightly from the protective member 15 (e.g. , about 0.5 mm to 2 mm in height). The protection member 15 extends on the rear edge 5c of the array substrate 5 to prevent the optical fiber 1 from being in direct contact with the rear edge 5c of the array substrate 5 .

The protective member 15 is made of a soft, bendable material such as rubber, silicone or nylon. Preferably, the protective member 15 and the optical fiber covering part 2 have good adhesion and a relatively large elongation at break. The protective member 15 is formed to have a certain length (for example, preferably about 3 mm to 5 mm) extending from the rear end of the array substrate 5 . The raised portion 15a is preferably tapered to prevent bending stress from being applied to the optical fiber. Also, the protection member 15 is positioned for fixation by disposing its top end adjacent to the shoulder of the step portion 5d on the base portion 5b of the array substrate 5 .

In the structures of FIGS. 5A and 5B , the bare optical fiber portion 3 positioned by the V-groove 7 is bonded by the first adhesive 11 similarly to the case of FIG. 1 . The top end portion of the optical fiber covering portion 2 is bonded to the base portion 5 b by the second adhesive 12 . The bare fiber portion 3 between the first and second adhesive is bonded by the third adhesive. The first adhesive 11 is a relatively hard adhesive having a Young's modulus greater than 500 MPa after hardening and a viscosity of 10 Pa·s or less before hardening. The second adhesive 12 is similar to the first adhesive 11, and is a higher material having a Young's modulus greater than 500Mpa after hardening and a viscosity of 10 Pa.s or greater than the first adhesive 11 before hardening. Relatively hard adhesive with high viscosity. And, the third adhesive 13 is a relatively soft adhesive resin softer than the first adhesive 11 having a Young's modulus of less than 500 MPa.

The second adhesive 12 for bonding the optical fiber covering portion 2 to the array substrate 5 is applied to cover the protective member 15 mounted on the array substrate 5 in FIG. 5A. Also, the second adhesive 12 is applied to cover a portion of the fiber covering portion 2 protruding from the top end of the protective member 15 and a portion of the protective member 15 mounted on the array substrate 5 in FIG. 5B. Therefore, a pulling force in the longitudinal direction of the optical fiber 1 is prevented from being directly applied to the bare optical fiber portion 3 engaged in the V-shaped groove 7, as shown in the case of FIG. 1 .

The protective member 15 is provided to extend on the rear edge 5 c of the array substrate 5 and serves as a spacer that prevents the optical fiber 1 from coming into direct contact with the array substrate 5 . Moreover, the optical fiber 1 is not easily damaged by the rear edge of the array substrate 5, or is not easy to be excessively bent under the optical fiber array 4, so as to reduce breakage or reduce transmission loss, without making the rear edge of the array substrate 5 as A smooth surface, as shown in Figures 3A-3C. However, even when the protective member 14 or 15 is used, the rear edge of the array substrate 5 may be formed by a tapered or arc-shaped smooth surface, as in the case of FIGS. 3A-3C. From Figures 1 to 5A, an optical fiber is shown, but the present invention is not limited to optical fibers. That is, optical fibers can be fixed to a substrate to form an optical fiber array in the present invention.

As can be seen from the above description, with the present invention, it is possible to include spliced portions of different optical fibers having different mode field diameters in an optical fiber array. Therefore, the optical fiber is easily introduced into a small space inside the optical communication unit, so that the unit can be miniaturized. Also, a protective member is provided to prevent the optical fiber from contacting the rear edge of the optical fiber array, thereby reducing breakage or preventing an increase in transmission loss. In addition, the optical fiber is spliced to the optical fiber array using three types of adhesives that differ in Young's modulus after hardening or in viscosity before hardening, so that the optical fiber is strong enough to resist pulling force and can prevent damage caused by temperature changes. resulting in increased transmission loss.

Claims (13)

1. fiber array comprises:

The different fiber that has different mode field diameters by joint forms an optical fiber, and this optical fiber has fibre coating part that applies fibre coating and the nuditing fiber part of removing fibre coating, the bonding part that the central authorities of this nuditing fiber part have different fiber;

Be used for installing the array substrate of optical fiber thereon, this array substrate has fiber alignment part and base part, and this fiber alignment partly has the nuditing fiber V-shaped groove partly that is used to place optical fiber;

The pressurizer parts are used for this nuditing fiber partly is pressed in the V-shaped groove of array substrate; And

First bonding agent is used for this nuditing fiber is fixed to the V-shaped groove of array substrate,

The bonding part that it is characterized in that different fiber is placed on this array substrate;

Wherein this fiber array further comprises:

Second bonding agent is used for the base part of the fibre coating partial fixing of optical fiber at array substrate; And

The 3rd bonding agent is used for covering and fixing the nuditing fiber part that does not place V-shaped groove,

Wherein first bonding agent has 500Mpa or bigger Young modulus and had 10Pa.s or littler viscosity before hardening after sclerosis, second bonding agent had the viscosity bigger than the viscosity of first bonding agent before sclerosis, and the 3rd bonding agent has the Young modulus littler than the Young modulus of first bonding agent after sclerosis.

2. fiber array according to claim 1, wherein different fiber is melted joint in the bonding part.

3. fiber array according to claim 2, wherein nuditing fiber partly has a mould field conversion portion that forms by the bonding part heating to different fiber.

4. fiber array according to claim 1, wherein this bonding part is placed on the base part of array substrate.

5. fiber array according to claim 1, wherein this bonding part is placed in the V-shaped groove.

6. fiber array according to claim 5, wherein this V-shaped groove has sunk part, and wherein this bonding part is placed in the sunk part of V-shaped groove.

7. fiber array comprises:

The different fiber that has different mode field diameters by joint forms an optical fiber, and this optical fiber has fibre coating part that applies fibre coating and the nuditing fiber part of removing fibre coating, the bonding part that the central authorities of this nuditing fiber part have different fiber;

Be used for installing the array substrate of optical fiber thereon, this array substrate has fiber alignment part and base part, and this fiber alignment partly has the nuditing fiber V-shaped groove partly that is used to place optical fiber;

The pressurizer parts are used for this nuditing fiber partly is pressed in the V-shaped groove of array substrate; And

First bonding agent is used for this nuditing fiber is fixed to the V-shaped groove of array substrate,

The bonding part that it is characterized in that different fiber is placed on this array substrate;

Wherein this array substrate has the rear end part of taper or arc.

8. fiber array comprises:

The different fiber that has different mode field diameters by joint forms an optical fiber, and this optical fiber has fibre coating part that applies fibre coating and the nuditing fiber part of removing fibre coating, the bonding part that the central authorities of this nuditing fiber part have different fiber;

Be used for installing the array substrate of optical fiber thereon, this array substrate has fiber alignment part and base part, and this fiber alignment partly has the nuditing fiber V-shaped groove partly that is used to place optical fiber;

The pressurizer parts are used for this nuditing fiber partly is pressed in the V-shaped groove of array substrate; And

First bonding agent is used for this nuditing fiber is fixed to the V-shaped groove of array substrate,

The bonding part that it is characterized in that different fiber is placed on this array substrate;

Wherein this fiber array further comprises:

Be used to protect the guard block of the optical fiber that extends in the back edge of array substrate.

9. fiber array according to claim 8, wherein this guard block has and is used for the tube shape of receiving optical fiber within it.

10. fiber array according to claim 8, wherein this guard block forms by a mould.

11. fiber array according to claim 8, wherein this guard block part of extending on array substrate is a taper.

12. fiber array according to claim 8, wherein this guard block covers the fibre coating part.

13. fiber array according to claim 8, wherein this array substrate has the step part that is used for installing guard block thereon.

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